Process for preparing granules of hydrophilic vitamins

Abstract

The present invention relates to a process for preparing granules of a hydrophilic vitamin with polyvinylpyrrolidone as binder in a fluidized bed granulator, to the granules of a hydrophilic vitamin obtained by said process, to tablets made with said granules of a hydrophilic vitamin, to mixture of L-ascorbic acid for direct tabletting and tablets made with said mixtures.

1 - 14 . (canceled) 
   
   
       15 . A process for preparing granules of a hydrophilic vitamin for direct compression comprising spray-coating powder of a hydrophilic vitamin, said powder having a size such that not lower than 80 weight percent of the powder passes through a 200-mesh screen (75 μm screen), with a solution of polyvinylpyrrolidone having a K-value of from 70 to 100 under constant agitation in a fluidized bed granulator until the total amount of polyvinylpyrrolidone has reached from about 0.5 to 1.9 weight percent relative to the total weight of polyvinylpyrrolidone and hydrophilic vitamin and wherein the amount of hydrophilic vitamin in the final granules is at least 98.1 weight percent. 
   
   
       16 . The process of  claim 15 , wherein said hydrophilic vitamin is L-ascorbic acid. 
   
   
       17 . The process of  claim 15 , wherein the K-value of the polyvinylpyrrolidone is from 90 to 98. 
   
   
       18 . The process of  claim 15 , wherein the total amount of polyvinylpyrrolidone is from 0.8 to 1.6 weight percent relative to the total weight of polyvinylpyrrolidone and hydrophilic vitamin. 
   
   
       19 . The process of  claim 15 , wherein the final granules have been dried up to a solvent-content of less than 1 weight percent. 
   
   
       20 . A granule of a hydrophilic vitamin, wherein said granule is produced by spray-coating powder of a hydrophilic vitamin, said powder having a size such that not lower than 80 weight percent of the powder passes through a 200-mesh screen (75 μm screen), with a solution of polyvinylpyrrolidone having a K-value of from 70 to 100 under constant agitation in a fluidized bed granulator until the total amount of polyvinylpyrrolidone has reached from about 0.5 to 1.9 weight percent relative to the total weight of polyvinylpyrrolidone and hydrophilic vitamin and wherein the amount of hydrophilic vitamin in the final granule is at least 98.1 weight percent. 
   
   
       21 . The granule of  claim 20 , wherein said hydrophilic vitamin is L-ascorbic acid. 
   
   
       22 . The granule of  claim 20 , wherein the K-value of the polyvinylpyrrolidone is from 90 to 98. 
   
   
       23 . The granule of  claim 20 , wherein the amount of polyvinylpyrrolidone is from 0.8 to 1.6 weight percent relative to the total weight of polyvinylpyrrolidone and hydrophilic vitamin. 
   
   
       24 . The granule of  claim 20 , wherein said granule has a solvent-content of less than 1 weight percent. 
   
   
       25 . A vitamin tablet produced by directly compressing one or more granules of  claim 20 . 
   
   
       26 . A mixture for direct tabletting, said mixture consisting of (1) L-ascorbic acid granules for direct compression, wherein said granules comprise at least 90% by weight of L-ascorbic acid, (2) from 0.25 to 0.75% by weight, based on the total weight of said mixture, of stearic acid, (3) from 2 to 20% by weight, based on the total weight of said mixture, of a microcrystalline cellulose, and (4) optionally at least one disintegrant selected from the group consisting of tow-substituted hydroxypropyl cellulose, carboxymethylcellulose, croscarmelose, carmelose, crospovidone, and sodium starch glycolate. 
   
   
       27 . A mixture for direct tabletting, said mixture consisting of (1) L-ascorbic acid granules for direct compression, (2) from 2 to 16% by weight, based on the total weight of said mixture, of a microcrystalline cellulose, (3) at least one lubricant, and (4) optionally at least one disintegrant selected from the group consisting of low-substituted hydroxypropylcellulose, carboxymethylcellulose, croscarmelose, carmelose, crospovidone, and sodium starch glycolate, and wherein the content of L-ascorbic acid in said mixture is from 82 to 95% by weight, based on the total weight of said mixture. 
   
   
       28 . An L-ascorbic acid tablet produced by directly compressing a mixture, wherein said mixture consists essentially of the mixture of  claim 26 .